cn vs zh

why does the website (and the repo) use `cn` instead of `zh`? the former is a [country code for the prc](https://en.wikipedia.org/wiki/China#:~:text=ISO,CN), while the latter is [a language code for chinese](https://en.wikipedia.org/wiki/Chinese_language#:~:text=ISO,zh). i have no intention of being offensive or anything, i'm just curious about the justification behind the current decision.